Fatty acid treatment



as fat splitting.

Patented Dec. 29, 1953 Martin David Reinish, Brooklyn,

,7 Patrick Caldarera, Flushing, -to Colgate-IMmolive-Peet City, N. J., a corporation of and Joseph N. Y., assignors Company, Jersey Delaware No Drawing. Application November 10, 1950, Serial No. 195,148

'fatty'glycerides into free fatty acids having improved color properties, and more particularly to a process that includes the treatment of free fatty acids of the kind indicated in such manner as substantially to prevent or at least greatly retard discoloration upon storage of such fatty acids.

The conversion of fatty glycerides into free fatty acids and glycerol is known in the industry This conversion involves the hydrolysis of the glycerides, which generally speaking are glyceryl esters of fatty acids of natural origin, into glycerol and the corresponding free fatty acids. The employment of water for this conversion performs the dual function of hydrolyizing the glycerides to form glycerol and free fatty acids while at the same time dissolving theglycerol so formed. The splitting of the fatty material into glycerol and fatty acids may be assisted by the use of suitablecatalysts and elevated temperatures as is well known in the art.

The reaction product of the fat-splitting operation is composed of the water-glycerol solution and the fatty acid phase, which may be physically separated one from the other by a definite wateroil interface. The crude fatty acids leaving the fat splitter are passed through a cooler, a surge drum and then into a decanter where water is mechanically separated, whereupon they are introduced into a dehydrator where essentially all of the residual water is removed. The dry fatty acids are then introduced into a still for distillation. The distilled acids are then conveyed to a suitable storage tank.

It has been found that processes of the above nature produce fatty acids which, although initially relatively light in color, upon standing for a relatively short period of time become very considerably discolored. This is apparently due to the presence, probably in the original fatty glyceride materials undergoing hydrolysis, of color bodies and/or latent color bodies of a complex nature which are, or become, associated with the fatty acids during their production. These bodies are apparently volatile and if not removed or deactivated remain associated with the free fatty acids upon distillation thereof, so that during subsequent storage of the freshly prepared, apparently highly purified, free fatty acids these color bodies or latent color bodies become functional and impart undesired color to the free fatty acids. In other words, the bodies in question may be said to give rise to undesired color reversion in the initially light, freshly produced free fatty acids. This discoloration adversely affects the marketable value ofthe free fatty acids.

It is therefore an object of this invention to provide a method for preventing discoloration of free fatty acids, even upon prolonged periods of storage; and especially a method for preventing or at least substantially minimizing color reversion of freshly prepared, initially light freefatty acids.

To accomplish the above mentioned object, this invention contemplates the introduction of an oxidizing agent to the material being processed at any stage of the process between theactual splitting of the fatty material-and the distillation of the crude fatty acids-produced as are'sult of the splitting operation. The oxidizing agent apparently oxidizes or-conver-tsthe color bodies and/or latent color bodies'of a relatively volatile nature to non-volatile 'color bodies, which during the subsequent distillation of the crude fatty acids remain behind intliestill bottoms.

Under conditions observed during thefat splitting process as previously described as normally applied to the splitting of a low-grade tallow and the subsequent distillation of the resulting tallow free fatty acids, the fatty acids obtained from the distillation step had an initial Lovibond color of 2-3 Red (5%" cell) which thereafter darkened to as much as Red upon 3 to 4 hours storage. The same procedure was then followed except that the present invention was made use of by bubbling air through the crude fatty acids in the surge drum. The temperature during this step was approximately 240 to 260 F. The contact time for the air in the surge drum was about one to two hours and the air flow rate about 13 cubic feet per minute. The fatty acids flow rate was about 7500 pounds per hour. The initial color of the free fatty acids obtained was 3-5 Red (5%, cell) which reverted to a maximum color of only 7 Red (5%." cell) upon storage over a similar period of time.

It is thus seen that discoloration of the initially relatively light fatty acids during storage, 1. e., color reversion, was substantially reduced by the process of the present invention which in its broadest aspects involves subjecting the crude freshly prepared fatty acids to an oxidizing agent at some stage during their production.

When using air as the oxidizing agent, the air flow rates and/or the contact times may be varied over rather wide limits without departing from the spirit of the invention, and with the production of substantially equally useful results. Thus, it has been found that air flow rates as high as 25 cubic feet per minute, at a crude fatty acids flow rate of about 7500 pounds per hour, give substantially complete elimination of color reversion of the distilled acids with no deleterious effects thereon. Moreover, contact times between the crude fatty acids and the air of as high as three hours give similar results.

When employing air as the oxygen-containing gas for achieving the objects of the present invention, it is important to insure intimate contact between the air and the crude fatty acids. This is brought about for instance by the violent agitation attendant upon bubbling the air through the freshly prepared crude fatty acids.

While the use of atmospheric oxygen as the oxidizing agent has been described above, other chemical oxidizing agents, such a a peroxide, may be employed for the same purpose, especially in cases where cost considerations happen not to be of primary importance. Thus, organic peroxides, such as benzoyl peroxide, and inorganic peroxides, such as sodium peroxide and hydrogen peroxide, may be employed. The oxidizing agent, whether in the form of atmospheric oxygen or in the form of other chemical oxidizing agents, may be introduced at any time following the fat splitting operation and prior to the distillation of the crude fatty acids.

What has been described is a particular embodiment of the present invention. Other embodiments apparent from the teachings herein are included within the spirit and scope of the appended claims.

What is claimed is:

1. In a method of producing light-colored fatty acids from natural fats and oils that includes hydrolyzing said fats and oils to produce crude fatty acids, introducing said crude fatty acids into a surge drum, and distilling said crude fatty acids,

the step that includes bringing the crude fatty acids into intimate contact with air by bubbling air through said crude fatty acids while in the A surge drum for a period of about 1 to 2 hours at a temperature of about 240 to 260 F. to oxidize the color-forming bodies therein to render said bodies non-volatile.

2. In a method of producing light colored fatty acids that includes the fat splitting of fatty material to produce crude fatty acids containing relatively volatile color-forming bodies, and distillation of said crude fatty acids to produce said light colored fatty acids, the step that comprises bringing said crude fatty acids prior to distillation into intimate contact with air for a period of about 1 to 2 hours at a temperature of about 240 to 260 F. by bubbling air through said crude acids to oxidize the color-forming bodies therein and render said color-forming bodies nonvolatile.

3. A method of obtaining light colored free fatty acids that comprises hydrolyzing natural fats and oils to produce crude free fatty acids containing relatively volatile latent color-forming bodies distillable with said fatty acids, intimately contacting said crude fatty acids containing said color-forming bodies with air for a period of about 1 to 2 hours at a temperature of about 240 to 260 F. by bubbling air therethrough to convert said color-forming bodies to relatively non-volatile color bodies which are substantially undistillable with said fatty acids, and thereafter distilling the crude free fatty acids so treated to obtain relatively pure free fatty acids having a greatly minimized tendency to discolor.

MARTIN DAVID REINISH. JOSEPH PATRICK CALDARERA.

References Cited in the file of this patent UNITED STATES PATENTS 

1. IN A METHOD OF PRODUCING LIGHT-COLORED FATTY ACIDS FROM NATURAL FATS AND OILS THAT INCLUDES HY DROLYZING SAID FATS AND OILS TO PRODUCE CRUDE FATTY ACIDS, INTRODUCING SAID CRUDE FATTY ACIDS INTO A SURGE DRUM, AND DISTILLING SAID CRUDE FATTY ACIDS, THE STEP THAT INCLUDES BRINGING THE CRUDE FATTY ACIDS TO INTIMATE CONTACT WITH AIR BY BUBBLING AIR THROUGH SAID CRUDE FATTY ACIDS WHILE IN THE SURGE DRUM FOR A PERIOD OF ABOUT 1 TO 2 HOURS AT A TEMPERATURE OF ABOUT 240* TO 260* F. TO OXIDIZE THE COLOR-FORMING BODIES THEREIN TO RENDER SAID BODIES NON-VOLATILE. 